CYANOTIC INFANT SENSOR

• US 20140206963A1
• Filed: 03/24/2014
• Published: 07/24/2014
• Est. Priority Date: 07/09/2004
• Status: Active Grant

• Current Assignee: Masimo Corporation
• Original Assignee: Masimo Corporation
• Inventors: Al-Ali, Ammar
• Granted Patent: US 9,480,422 B2
• Time in Patent Office: Days
• US Class Current: 600/323
• CPC Class Codes: A61B 2503/04 Babies, e.g. for SIDS detection
• CPC Class Codes: A61B 5/0059 using light, e.g. diagnosis by transillumination, diascopy, fluorescence A61B5/0093, A61B5/1455, A61B5/02416 and A61B5/0261 take precedence
• CPC Class Codes: A61B 5/14551 for measuring blood gases
• CPC Class Codes: A61B 5/14552 Details of sensors specially adapted therefor
• CPC Class Codes: A61B 5/7271 Specific aspects of physiological measurement analysis A61B5/316, A61B5/349 and A61B5/374 take precedence

Abstract

A pulse oximetry sensor comprises emitters configured to transmit light having a plurality of wavelengths into a fleshy medium. A detector is responsive to the emitted light after absorption by constituents of pulsatile blood flowing within the medium so as to generate intensity signals. A sensor head has a light absorbing surface adapted to be disposed proximate the medium. The emitters and the detector are disposed proximate the sensor head. A detector window is defined by the sensor head and configured so as to limit the field-of-view of the detector.

Claims

1. A method for determining a physiological parameter, the method comprising:

receiving one or more intensity signals responsive to light of a plurality of wavelengths attenuated by body tissue of a patient;

electronically retrieving mapping data including a relationship between DC response ratio data, ratio-of-ratios data, and oxygen saturation data;

electronically calculating a DC response ratio value responsive to said one or more intensity signals;

electronically calculating a ratio-of-ratios value responsive to said one or more intensity signals; and

electronically deriving an oxygen saturation measurement responsive to said mapping data.

2. The method of claim 1, comprising electronically displaying the patient'"'"'s oxygen saturation responsive to said oxygen saturation measurement.

3. The method according to claim 1, wherein said calculating said DC response ratio comprises calculating said DC response ratio as a ratio of a detected incident intensity of the light at a first wavelength of said plurality of wavelengths to a detected incident intensity of the light at a second wavelength of said plurality of wavelengths.

4. The method according to claim 1, further comprising emitting said light from a plurality of emitters and receiving said light at one or more detectors.

5. The method according to claim 4, wherein a first subset of the plurality of emitters have been matched to transmit light at a first wavelength and a second subset of the plurality of emitters have been matched to transmit light at a second wavelength, wherein said matching of said emitters to said first and second wavelengths reduces variations in a mean pathlength ratio of said light traveling through said body tissue between said plurality of emitters and said one or more detectors.

6. The method according to claim 4, wherein an emitted DC intensity ratio of said plurality of emitters has been matched to a first predetermined constant, and wherein said matching of said emitted DC intensity ratio to said first predetermined constant further reduces variations in said mean pathlength ratio of said light.

7. The method according to claim 4, further comprising receiving said light at one or more detectors and generating said intensity signals from said light received at said one or more detectors.

8. The method according to claim 7, wherein a DC response ratio of said one or more detectors has been matched to a second predetermined constant, and wherein said matching of said DC response ratio to said second predetermined constant further reduces variations in said mean pathlength ratio of said light.

9. The method according to claim 7, further comprising limiting a field-of-view of said one or more detectors so as to substantially limit said light received at said one or more detectors to portions of said light that propagate entirely through said body tissue.

10. A pulse oximeter comprising one or more processors configured to execute the method of claim 1.

11. The pulse oximeter of claim 10, further comprising a plurality of emitters configured to emit said light and one or more detectors configured to detect said light.

12. The pulse oximeter of claim 10, further comprising a memory, said memory storing said mapping data.

13. The pulse oximeter of claim 12, wherein said memory comprises read only memory.

14. A pulse oximeter comprising:

a sensor configured to output one or more intensity signals responsive to light attenuated by body tissue of a patient wearing said sensor;

a memory storing mapping data representing relationships between DC response data, ratio-of-ratios data, and oxygen saturation data; and

a processor responsive to said output signals to determine a DC response and a ratio;

said processor configured to determine a measurement value responsive to said relationships stored in said memory.

15. The pulse oximeter of claim 14, further comprising a patient monitor housing for housing said processor and said memory.

16. The pulse oximeter of claim 14, further comprising a sensor housing for housing said memory.

17. The pulse oximeter of claim 14, further comprising a display configured to display said measurement value.

18. The pulse oximeter of claim 14, wherein said sensor comprises a plurality of emitters and one or more detectors.

19. The pulse oximeter of claim 18, wherein:

a first subset of the plurality of emitters are matched to transmit light at a first wavelength and a second subset of the plurality of emitters are matched to transmit light at a second wavelength;

an emitted DC intensity ratio of said plurality of emitters is matched to a first predetermined constant; and

a DC response ratio of said one or more detectors is matched to a second predetermined constant;

wherein said matching of said emitters to said first and second wavelengths, said matching of said emitted DC intensity ratio to said first predetermined constant, and said matching of said DC response ratio to said second predetermined constant reduces variations in a mean pathlength ratio of said light traveling through said body tissue between said plurality of emitters and said one or more detectors.

20. The pulse oximeter of claim 14, wherein said memory comprises read only memory.